Electrochemical cells have been formed in the past on the surfaces of silicon wafers or slabs. However, such cells have not been made in the past through providing wells which extend into the silicon whereby the entire chemistry of the cell is below the surface of the silicon. Further, such cells have not been made in the past to include connection through the silicon wafer to its back side so as to provide easy access to an integrated circuit which can process the signals developed by the electrochemical cell.
Planar electrochemical cells, with the electrodes and electrolytic medium on one surface of slabs or wafers various materials, including silicon, are known. However, such cells have not been made in the past with the sensing electrode being connected through the slab or wafer to another surface of the slab or wafer whereby easy access is provided to an integrated circuit on or in such other surface and which can process the signals developed by the electorchemical cell.
The present invention is directed to solving one or more of the problems as set forth above.